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Adobe DRM: a guide for publishers

Digital Rights Management (DRM) is any technological constraint on what a user can do with a document. Usually, DRM involves some kind of encryption that locks a document to a user’s identity, so that they can’t share it with anyone else. Whether you choose to use DRM on your ebooks is up to you, and should depend on your sales and distribution strategy for each book or list of books. At Electric Book Works we always recommend not using DRM; but we know not everyone agrees with us. The question you should ask yourself is not ‘Shall we go DRM-free’ or ‘What DRM should we use’, but ‘Do we need DRM on this?’ That said, if you do choose to use DRM, at some point you’ll have to choose DRM settings for an Adobe Content Server. Read on for guidance.

What is Adobe DRM?

There are three major DRM ecosystems in the book world: Amazon’s (for the Kindle), Apple’s (called FairPlay), and Adobe’s. Amazon and Apple use their own DRM systems for ebooks they sell. Most other major ebook distributors and retailers use Adobe DRM. An ebook with one kind of DRM cannot be opened with software that uses another (e.g. a PDF with Adobe DRM cannot be opened on a Kindle device or app.)

Adobe DRM is applied and managed on the distributor’s end with an Adobe Content Server.

On the user’s end, ebooks encrypted by an Adobe Content Server are opened and read by software built on an Adobe engine – technically, Adobe’s Reader Mobile SDK – such as Adobe Digital Editions (ADE), txtr and a range of e-ink readers (Sony, Bookeen, iRiver, etc.).

How does it work?

(If you don’t care how it works, skip down to ‘Choosing Adobe DRM settings’.)

Let’s say Joe Bloggs buys an ebook from (fictional) ebook retailer Fleebooks.com, downloads it and reads it on his computer. Here is what happens in the background, and where DRM fits in:

  • Fleebooks.com gets its catalogue from two big distributors, Ingram Digital and Gardners. Both distributors use Adobe Content Servers to deliver DRMed ebooks, and pay Adobe about $6000 a year for the software, and $0.22 each time someone buys an ebook.
  • Let’s say Joe’s ebook, Potato Farming in the Hebrides, happens to come from Ingram Digital.
  • Joe pays Fleebooks.com with his credit card, after which he clicks a link on Fleebooks.com that says ‘Download ebook’.
  • He clicks the link, and actually downloads a small .acsm (Adobe Content Server Message) file. He thinks he’s downloaded the ebook, but he hasn’t yet. (Some retailers are worse than others at explaining this to customers.) It’ll be some thing like Potato_Farming_in_the_Hebrides.acsm.
  • If he has suitable Adobe-RMSDK-based software on his computer already (e.g. Adobe Digital Editions), that software can open the .acsm file. If he hasn’t installed such software, his computer won’t know what to do with the .acsm file. (Joe may get frustrated at this point and call the Fleebooks.com call centre for help; or just never buy another ebook.) But let’s say Joe has ADE installed, and it opens the .acsm file.
  • The .acsm file carries instructions and a hyperlink that tell ADE to get Joe’s new ebook straight from Ingram’s ACS.
  • Joe’s ADE and Ingram’s ACS have a little conversation, in which ADE gives ACS Joe’s Adobe ID (joe@bloggs.com), and the ACS packages an ebook file specifically for that ID.
  • At the same time, Ingram’s ACS has a conversation with Adobe’s own signing server (either the US one or the UK one). The signing server checks that everyone is who they say they are, and gives the go-ahead for the ACS to deliver Joe’s ebook.
  • If any of this fails, the download fails and Joe will have to try opening the .acsm file again. (ADE usually remembers that there was an unfinished download and may prompt Joe to retry.)
  • While ADE, the ACS, and Adobe’s signing server are having their conversations, nothing happens on Joe’s screen. If Joe’s Internet connection is fast, this will take a couple of seconds and Joe may not notice the delay. If Joe’s on a slow connection, the delay may take long enough, say twenty seconds, before ADE says ‘Downloading document’ and shows a progress bar. Joe may think nothing’s happening and give up. Let’s say he doesn’t.
  • The ebook now being downloaded by ADE has been encrypted by the ACS and can only be opened on a computer authorised with Joe’s Adobe ID.
  • Once the ebook has finished downloading, it will open in ADE, and Joe can start reading.
  • When the ebook’s publisher, Potatorama, placed the ebook with Ingram, they chose particular Adobe DRM settings that will affect what Joe can do with his ebook. In this case, let’s say, Potatorama said Joe could copy–paste 30 passages a month from the ebook, and cannot print from it at all. While reading the ebook then, Joe’s print button is greyed out. Once he’s copied 30 passages into emails to his friends in one month, he won’t be able to copy any more till next month.

Here’s an image that summarises this process.

Aggregated, DRM-based ebook distribution

Aggregated, DRM-based ebook distribution

Choosing Adobe DRM settings

Adobe Content Server 4 (the latest version of ACS) allows you to control many different security settings (e.g. at what resolution an ebook can be printed, whether the ebook will expire, etc.). But most distributors, such as Ingram Digital, will only let publishers choose from two key settings (mostly to make the publisher’s decisions easier):

  • How much a user can print from an ebook, and how often.
  • How much a user can copy (for pasting elsewhere) from an ebook, and how often.

For each of printing and copying, publishers can also choose ‘unlimited’.

No matter what the publisher chooses, the ebook cannot be opened on a computer that has not been authorised with Joe’s Adobe ID.

In the example above, Joe could copy (for pasting) up to 30 passages a month, and he couldn’t print at all. As the publisher you have to decide how much to stop your readers from doing. Remember, the more you constrain them, the more frustrated they may be.


Remember: a user doesn’t have to be a skilled hacker to get around DRM. ‘Print screen’ or typing will make a pretty good copy of your book. If someone has a good reason to make a pirated edition of your ebook, they will find a simple way to do so. Do not think DRM can prevent widespread pirating of your popular books.

What if I don’t want DRM?

Most distributors who use DRM will assume publishers want it by default. If you don’t want DRM on your ebooks, you must ask specifically for that. You may have to explain very clearly that you do not want your ebooks packaged and delivered by an ACS.

Who wins and who loses from DRM?

  • If you have no DRM, Adobe loses its $0.22 per sale. While on the job, Adobe salespeople will tell you security is very important and that you need DRM.
  • DRM costs distributors money (Adobe fees as well as the salaries of highly skilled technical staff). A DRM-free delivery process would be cheaper to run. However, distributors need publishers to feel at ease, including the conservative ones. They will tell each publisher what they think that publisher wants to hear.
  • DRM costs retailers money. Not only do distributors pass on some Adobe DRM costs to them, but for retailers, the majority of customer-service problems with ebooks have to do with DRM. This is expensive and chases customers away. Retailers spend a lot of energy on making their sales process easy, because this brings customers back as much as good prices do. They will tell you that DRM is a bad idea – one they have to live with as long as publishers require it.

No one knows whether DRM is good or bad for publishers. Brian O’Leary at Magellan Media Partners spends a lot of time trying to put actual data to this question, and trying to convince publishers not to make a DRM call based on anecdotal evidence.

Good luck with your decision.

Arthur Attwell 24 August 2010
This information is more than two years old, and may no longer be accurate.